Deep Learning is about learning multiple levels of representation
and abstraction that help to
make sense of data such as images, sound, and text.
For more about deep learning algorithms, see for example:

The tutorials presented here will introduce you to some of the most important deep learning
algorithms and will also show you how to run them using Theano. Theano is a python library that makes writing deep learning models easy, and gives the option of
training them on a GPU.

The algorithm tutorials have some prerequisites. You should know some python,
and be familiar with numpy. Since this tutorial is about using Theano, you
should read over the Theano basic tutorial first. Once you’ve done that,
read through our Getting Started chapter – it introduces the notation, and [downloadable] datasets used in the algorithm tutorials, and the way we do optimization by stochastic gradient descent.

The purely supervised learning algorithms are meant to be read in order: